The present invention relates to a drill hole filling method, wherein the first step comprises the drilling of a hole by using a tubular drill rod through which some flushing medium is passed during a hole-drilling operation through at least one aperture in a crushing tool into an annular space defined by the hole and the outer surface of a drill rod for carrying crushed matter out of the hole.
A drill hole formed as described above can be used in a variety of ways for achieving the object of the invention in mining operations. First of all, a drill hole can be filled with a soldering material for anchoring a pit-bracing bolt in the hole. Secondly, a hole can be used for bracing and plugging poor-quality rock by injecting reinforcing material in rock fissures through the drill hole. After this operation, it is naturally possible to effect the fixation of a bolt by means of a soldering material. A third application is the filling of a drill hole with an explosive. In any event, a filler is in a liquid form. In the two first-mentioned cases, the question is primarily about improving the strength and density of rock and in the third case about performing the actual mining work.
The prior art deals mostly with fixation methods of anchoring bolts. For example, Finnish Patent No. 15277 discloses a method for anchoring rods in a ground or a bedrock. This method involves the use of a drill rod which is fitted with a drill bit and surrounded by a pipe during a drilling operation. The pipe is removably fastened to the drill rod and drill bit. During the drilling operation, a flushing medium is supplied into a space confined by the anchoring rod and the pipe, and after the drilling operation, the space is filled with a binder. During the supply of the binder, the pipe is being withdrawn from a drill hole, whereby the drill rod together with its drill bit remains in a drill hole as an anchoring rod and is anchored by the action of a binder.
Thus, the method disclosed in the Finnish Patent No. 45277 specially built drill rods and drill bits and the only purpose the cited method can be used for is the anchoring of such rods.
On the other hand, prior known is also a method, wherein the fixation of an anchoring bolt is effected by first drilling a hole with a percussion drill followed by withdrawing the drill rod from the drilled hole and introducing into the hole a separate filler supply tube or pipe. Through this tube or pipe a filler is delivered into the hole, whereafter an anchoring bolt is inserted into the hole plugged with the filler.
The above technology is also unfavorable for the reasons discussed below:
First in a broken rock stratum, always found in areas that require reinforcement; the insertion of a pipe or tube in a drill hole is difficult because of rock material tumbling into the hole. In addition, a tube or pipe tends to jam in the hole for the same reason.
Secondly, bringing a pipe or a tube accurately to the mouth of a drill hole is accidental, especially with a hole drilled in uneven terrains since, due to uneven terrain, the drill rod shifts out of normal center and the drill rod also bends at the starting stage.
Furthermore, additives required especially in areas to be reinforced for speeding up the setting of a soldering agent cannot be used, since the setting of a soldering agent in a delivery tube has been possible. After a delivery operation, the mixing apparatus still contains some mixed mass which sets rapidly. The mixing of an additive with a soldering mass is incomplete since mechanical blending cannot be achieved. Neither does the rotation of a reinforcing bolt for mixing purposes in an overhand drill hole filled with a soldering agent provide a desired result, since it can form voids around the bolt in a drill hole with soldering agent trickling out of the drill hole.
Also, circulation of a soldering agent in a supply line for preventing the setting has not served the purpose since the portion entering the drill hole and required by a supply system would not be circulated.
The insertion of a soldering agent tube or pipe as a separate operation is an unnecessary, timeconsuming process.